Sprocket chain lubrication



Dec. 14, 1943. w, M, ALBRECHT 2,336,913

sPRocxfET CHAIN LUBRICATIQN Filed Feb. 11, 194s wf/f Patented Dec. 14, 1943 SPRO CKET CHAIN LUBRICATION Walter M. Albrecht, Milwaukee, Wis., assignor to Chain Belt Company, Milwaukee, Wis., a corporation di' Wisconsin .Application February 11, 1943, Serial No. 475,531

'l Claims.- (Cl. 'I4-257) This invention relates to the lubrication of sprocket chains such as are widely used for power transmission, conveyors, and other purposesand has for one ofvits objects to provide a simple, relatively inexpensive and eifecti've arrangement for improving the lubrication of the articulating joints between adjacent links of such chains, by sealing the journals of such joints against the escape of lubricant therefrom', as well as against the entrance of extraneous deleteriousI matter thereto, whereby wear on and/or damage to the bearing surfaces may be reduced and the life of the chain materially lengthened.

As will appear more fully below, the invention is readily applicable, with substantially a minimum of change in the standardized conventional parts, to practically all types of sprocket chains having articulating joints comprising chain pins carried by one link and journaled in a bearing provided'in the adjacent link. It is well known that due to the relatively high bearing pres-l sures developed in these joints, it is desirable that they be constantly lubricated; also, particularly in the case of chains operating in the presence of deleterious materials, as in the conveying of pulverulent or granular abrasive or erosive substances, the journals preferably should be sealed against the entrance of such substances to protect the bearing surfaces'against the harmful action thereof. f

While the problem has been heretofore appreciated, and attempts have been made to solve it, so far as I am aware none of them has proved commercially successful. For the most part, the prior proposals have involved the material alteration of the standard chain parts, which of itself tended to add prohibitvely to the cost ofmanufacture through the necessity for new tooling, patterns and/or modes of procedure, and in some instances actually seriously reduced the load capacity of the chain below its established rating. In still other cases the prior proposals called for the use of more or l'ess complicated and relatively expensive additional elements, manyl of which in practice failed to effectively perform their intended functions. With the shortcomings of these previous attempts to solve the problem in mind, the present invention has been developed for application to all types of articulating-joint chain 'at a minimum of cost, without substantial alteration of the standard chain parts, and without appreciably affecting the rated load-carrying capacity of the tively perform its intended purpose of preventing escape of lubricant from the pin journals while excluding extraneous deleterious matter therefrom, through thousands of tlexings of the chain, thus indicating long eillcient life.

While as above indicated, the invention may nd utility in chains of many different types, for

ypurposes of the present disclosure its applica- .transmission and conveyer work, with the present invention embodied therein;

Figure 2 is an enlarged fragmentary sectional view, taken approximately on the plane indicated by the line 2-2 of Fig. 1, looking in the direction of the arrows;

Figure 3 is a perspective view of one of the sealing elements;

Figure 4 is a fragmentary longitudinal sectional view, showing the application of the invention to an open link. 'straight side-bar form of chain widely used for conveying purposes; and

Figure 5 is a view similar to Fig. 4 illustrating use of the invention in a block chain.

Referring more particularly to Figures 1 and 2 of the drawing, the offset side-bar chain shown therein comprises fabricated links L. each of which includes a pair of transversely spaced sidebars I0 and II, the opposite ends of which are laterally oset to produce a link having a wide end and a narrow end, the latterbeing receivable within the wide end of the next adjacent link, as will be clear from Fig. 1. The side-bars are apertured at each end, as indicated at I2 and I3, the apertures I2 at the narrower end of the link being of somewhat greater diameter than the apertures I3 at the wider end, and receiving the opposite end portions of a-tubular sleeve or bushing I4, which is press-fitted into said apertures thus providing a rigid U-shaped structure. With the apertures I3 of one link alined with bore I5 of the bushing I 4 of the adjacent link,

chain; and actual trials have show it to effeca chain pin I6 is slipped through them to articulately connect the links. The said pin has a preformed head I1 at one end and a transverse aperture I8 at the other end to receive a retaining cotter I 9. The chain pins I6 may be held against rotation in the apertures I3 in any appropriate manner, as by iiats I6 formed on them adjacent their unheaded ends, engageable with as to provide a working fit between the two so that the links may articulate,and forrbest working conditions the bearing surfaces of these parts should of course be lubricated. To this end a suitable lubricant may be introduced to the bearing surfaces throughapertures 23 in theside i bars and thegbushingwall.

-As above'indicated, itis desirable to prevent the escape ofv such lubricant fat; the ends of the bushings I4, so as to reducevthe frequency yof supplying the lubricant; likewise, it is desirable to prevent entrance of extraneous matter into the bearings; and to these ends sealing members 25,' constituting the gist of the present inventlon, are provided at these points.

The flexibility of the lip 29 and its engagement with the pin in axially spaced relation to the end of the bushing I4, enables the sealing element to accommodate the usual tolerances permitted in the dimensions of the parts, and facilitates asi sembly.

While working clearances 38 are provided be- Y tween the complementary overlapping faces of the aperturesl I3 are countersunk, as indicated at In previous chain constructions of this type,

through the side-bars III and II so that the bushing ends were flush. withthe outer side faces of the'said side-bars.

and terminatasay, 11;" short of the side-'bar faces, thus providing a circular vrecess or counterbore 26 atv each side-bar outerrface,` in each of which recesses a sealing member is positioned. e K

Asbest shown in Figs. 2 and 3, these sealing members each comprisev a metallic annulus 21, of

In the present instance,l however, the bushings are shortened somewhat vthe bushings I4 have extended'V completely L-shaped cross section, and a resilient annulus "28," of natural rubber, synthetic" rubber, o'r

equivalent material` secured to said metal annulus. circumferential body portion 28', which fits in and n I8, all as'will'be readily understood from Fig. 2. The diameterI of the aperture 30 of the lannulus 28 is preferably `slightly less than the diameter of the chain pin Ito insure intimate sealing eny gagement between the two elements.

When viewed edgewisa the flexiblelip portion 29 of theannulus 28 may be normallystraight and substantially alined with the outer circumferential body portion 28' thereof; but preferably the annulusl 28T-is pre-formed ywith the Vsaid lip portion curved somewhat, as indicated in Figs. 2 and 3. In either-case, the engagement of the lip with the circumferential surface of the pin I8 willapproximate a line contact conducive to a minimum of frictlo'nal resistance to articulating movements of the 'joint compatible with an emcient sealing engagement between the lip andthe pin surface. Further, in either case the zone of contact between'the lip and the pin surface is spaced in an axial direction from the end'face of the bushing I4. thus', in conjunction with the supporting metallic annulus 21, providing an annular chamber or pocket 35 adapted to receive Y and retain lubricant, and supply it to the working'cle'arance 38 between'the pin and` bushing bearing surfaces. The lubricant supply ducts 23, vwhiley communicating at their'inner ends with said clearance, preferably are so positioned as to also discharge to the chambergllt as indicated in Fig. 2.

The resilient annulus comprises an outer is suitably bonded to the L-shaped metal annulus 1 21, and an inner .circumferential portionV 29, con- 3I. This, together with the fact that the seal members 25 are seated in the counterbores or recesses 28 with the outer end faces of the seals substantially ush with the outer faces of the inner side-bars, prevents damaging contact bey tween the inner faces of the outer side-bars and resilient sealing elements 28 when the links shift axially of the pins I8 during operation and lessen or completely close the clearance spaces 38. Even should the sealing members 25 not be completely flush with the'side-'bar' faces, such axial shifting of the links would bring the inner face of the outer side-'bar into engagement with the end face of the'short leg of the L-shaped metallic supporting annulus 21 and thus yprotect the resilient annulus 28 against damage.

In Fig. 4 there is illustrated the application of the invention to an open link straight side-bar conveyor chain, wherein the links L are of hollow rectangular form having straight side-bars 40 connected at their ends by integral transverse barrels 4I provided with bores 42 for receiving and journaling the chain pins 43. A series of such such links is connected together in spaced relation by independent straight side bars 44 having apertures 48 for receiving the ends of the chain pins 43, which are heldagainst rotation therein as by ats 48 and restLined against dislodgment by heads 43' and cutters". The outer side faces of the links'L' are counterbored as at 48 to receive the sealing-elements 25, and the complementary faces of the side-bars 44 are countersunk as at 49 to accommodate the lips 29 of said elements.

The chain shown in Fig. 5 is somewhat similar to that illustrated in Fig. '4, except that solid or block links L" are employed instead of open rectangular links L,-and the ends of the pins 43 are'headed or riveted in the straightindependent side-bars 44.

As above indicated, the depth of the recesses Y or counterbores 28, 48-and of the countersinks 3I,

49 need be say only 11s 0f an inch for a chain of four inch pitch, which'is relatively small as com- 1 pared to the other dimensions of such a chain, and

f 1. Y In a sealing arrangement for an articulating joint of a sprocketchain having a link element and a chain pin carried thereby: a second link element having a portion disposed in overlapi relative to the other both circumferentially and pin at the end of said bore; and a sealing eler ment seated in said recess, comprising an annulus having a substantially rigid outer circumferential portion and a flexible inner circumferential portion including a lip yieldably engaging the surface of the chain pin to prevent passage of material axially to and from the journal bearing, the outer end face of at least the outer circumferential portion of said sealing element being substantially flush with the end face of its carrying link element, whereby the flexible portion of the sealing annulus may not be damaged through reduction or elimination of the clearance between the overlapping portions of the two link elements due to shifting of one relative to the other axially of the pin.

2. A sealing arrangement according to claim 1, wherein the flexible lip portion of the sealing annulus is tapering and engages the pin surface in a zone axially spaced from the bottom of the recess to provide an annular lubricant-retaining pocket.

3. A sealing arrangement according to claim 1, wherein the flexible lip portion of the sealing annulus is ared axially outwardly and engages the pin surface in a zone axially spaced from the bottom of the recess to provide an annular lubricantretaining pocket; and the carrying link element is provided with a duct for supplying lubricant to said pocket.

4. A sealing arrangement according to claim 1, wherein the flexible lip portion of the sealing annulus is tapering and flared axially outwardly to engage the pin surface with a substantially line contact in a zone axially spaced from the bottom of the recess.

5. A sealing arrangement according to claim 1,

wherein the flexible lip portion of the sealing annulus is ared axially outwardly and engages the pin surface in a plane beyond the end face of its carrying link portion, and the overlapping portion of the companion link element is recessed to prevent contact and damage to said lip portion.

6. A sealing arrangement according to claim 1, wherein the sealing annulus of the sealing element is of resilient material, and its outer circumferential portion is carried and rigidly supported by a metallic annulus.

'7. In an articulating joint for sprocket chains, a link element comprising companion spaced side bars having alined pin-receiving apertures in a portion thereof, the inner faces of said bars being countersunk around said apertures; a chain pin mounted in said apertures; a second link element comprising companion spaced side bars having alined bushing-receiving apertures in a portion thereof adapted to overlap the pin-carrying portion of said first element with working clearance between them; a tubular bushing rigidly mounted in said last named apertures for journaling a portion of said chain pin, said bushing terminating short of the outer faces of its side bars to provide an axially-shallow annular recess at each end of the pin bearing; and an annular sealing element seated in each of said recesses, the outward faces of the outer circumferential portions of which elements are substantially flush with the outward faces of their carrying side bars, and the inner circumferential portions of which sealing elements comprise ilexible lips engaging the surface of the chain pin to prevent passage of material to and from the pin bearing, said lips flaring axially outward across said working clearances and being accommodated by the countersinks in the rst named side bars,

whereby the lips are protected against contact with and damage by such side bars.

WALTER M. ALBRECHT. 

